Our organizations face changing circumstances: disruption of our markets, new regulations, the Corona virus forcing us to keep our distance and work from home. So our organizations, and we as the employees, have to change to stay competitive, compliant and safe. In nature, plants, animals and people also have to deal with changing circumstances. Sometimes we try to change what we find, sometimes we all just go with the flow. But in any case, we all – including plants, animals and people – have to do something to adapt.
Wadden Sea: ever changing
Recently, we went for a short holiday trip to the Wadden Sea in the north of The Netherlands. Yes, we are now allowed to get out of our houses, as long as we are careful, though our trip abroad was canceled… In that region, change is very visible. The Waddenzee or Wadden Sea is called a sea, but it is a large, shallow intertidal zone. So now you see the sea, and now you don’t, because a few hours later you get mudflats as far as the eye can see. The ferry boat to the island of Ameland has to wind its way and find a channel that is deep enough. And that channel tends to shift and silt up. So the captain has to pay attention and adapt, to be able to sail to the island, and the dredging companies have to work hard to keep the harbour and a route clear.
View from the island of Ameland to the mainland. A few hours ago, this was sea. Now it is mostly mud. And if you don’t mind getting dirty and a bit wet, you can walk to thg mainland.
The birds adapt to the tides
The birds are very much aware of the tides. They have their long-term genetic adaption of specific types of bills that allow for specific types of feeding. And that has to be combined with the short-term adaption of finding the right place and time to suit their needs.
Low water is great for the waders, who can stalk the mudflats and eat the juicy insects and shellfish that burrow in the mud.
The pied avocets catch crustaceans and insects by sweeping their bill through the shallow water or picking them from the mud.
Turnstones can’t probe deeply for their food, with those shorts bills. They turn stones to find it, as their name indicates. Or they just pick it from the sand at low tide.
Spoonbills need shallow water, to “spoon” for aquatic creatures. We have seen them appear in shallow pool when the tide was right at that place & time.
Spoonbills usually “spoon” small fish and shrimps, but shellfish like mussels are appreciated too.
Fishing birds like Terns have to fly to the right place to catch their fish. When the water is gone from the Wadden Sea, the Sandwich terns on the island of Texel fly to the other side, to the deeper North Sea. At high tide, they can find water and fish closer to their colony.
This Sandwich tern has caught a nice fish. He has to fly to water deep enough to harbour fish.
High water allows swimming birds like Eiders to dive for molluscs near the coast, where we could see them.
A lot of female Eiders were lounging and feeding in the water of the Wadden Sea, though sometimes they had to defend their catch from Gulls who tried to steal it.
Waders however, who prefer shallow water and mud, tend to get out of the way of all that water and find a refuge at high tide.
A flock of thousands of waders – mostly Knots but also some Bar-tailed Godwits – land on a high-water refuge. Unfortunately, today the water was higher than yesterday, so the little beach disappeared at high water and the flock has to leave early.
The plants adapt to salt water
The border between land and sea is not very clear cut in this region. At low water, the sea looks like land, with those extensive mudflat that you can walk on. At high water, the sea floods the land and plants end up with their feet in the water. The salt marshes have special plants, that have adapted to handle the salt water.
The glasswort and sea-lavendar in the salt marshes of De Volharding on Texel don’t mind the salt water that floods them at high tide.
The people adapt the landscape and seascape
The people living on the islands in the Wadden Sea appreciate their natural environment, but there are limits. If they let nature take its course entirely, not only the ferry channels will shift, but the islands themselves too: in some places the sea erodes the dunes and beaches, in other places the sea deposits the silt. So they need to dredge the harbours, to keep the sea where they need it. But they also have to take measures to keep the land where they need it. In gale force winds, the sea can break through and flood the land. Unless you protect the land with some serious dikes.
The dike protects the east side of the island of Texel. Now that we have the dike, we can also use it to provide cycling lanes and put some sheep out to graze.
Last year a new hybrid dike was constructed in the south-east, because the old dike could not guarantee the safety of the inhabitants, given the changing circumstances: sea levels are rising, the soil is compacting and getting lower and our rules are stricter. But our other requirements have also changed. Putting in a new traditional dike would take up a lot of agricultural space and damage the biodiversity. So they adapted and came up with a new solution: a “sand dike”, artificial dunes outside the dike. These can safely soak up the waves and provide a new habitat of dunes and salt marshes for wildlife.
Now we need the plants, the birds and the other animals to adopt the new dunes. The people have planted Marram grass to keep the sand in place. And they have transplanted a piece of salt marsh that would disappear under the new dunes to a new location: turf with some rare plants. At this time, the whole thing looks rather sandy, but we’ll have to wait and see if the plants and wildlife can adopt it, make it their own, or if they need some more help and change management.
A new “sand dike, the Prins Hendrikzanddijk, consists of artificial dunes, with marram grass to keep the sand in place and fences to catch more sand.
The birds and people adapt to each other
Birds who liked to nest in the salt marshes got in trouble when people put up a big dike on the east side of the island of Texel. Because people like birds, they dug some shallow pools right behind the dike, to provide some space for birds like waders, terns and geese. This works very nicely, though the birds and the people are still getting used to each other and adapting.
There used to be a colony of Sandwich terns in the north section, but the birds left. The experts think that they were disturbed, maybe by people walking their dogs. Terns nest on the ground, their nests in a ground scrape. So they don’t like dogs. Fortunately the terns re-established the colony a few miles south in the area. Apparently there are no dogs or other disturbances there, because the birds have seriously adopted that pool and its islands: there are over 6.000 pairs of Sandwich terns nesting there! We also saw plenty of avocets with chicks and oystercatchers with chicks.
The colony of Sandwich terns is a very busy place: noise, smelly and a feast for the eyes. This is only a very small section of it.
The Sandwich terns have adopted the artificial pool and island, to nest and rear their chicks
So that change went very well- sometimes it just works!
